Depreciation Flag Uncheck itself

Hi All,

When the user opens the Asset work bench and go to Quick Additions the form shows with "DEPRECIATE FLAG" Check but as soon user enter details it is Unchecked itself. Where the Tax book will have the "DEPRECIATE FLAG" due to which the Depreciation is not calculated on the CORPORATE book but it does on the Tax book. Please Advise.

Expense Book:

When We Initially Open the Asset Work Bench the “Depreciate”
flag is CHECKED

But once we enter the details the Depreciate Flag unchecked itself.

What might be the reason behind it.